Flash ECU general questions

[Prime12]

Greg, (or anyone else who is knowledgeable about Chrome ECU's)

I am seriously considering getting the new plug&play flash ECU and using Chrome V2 on my 97 VR4. I read through your past threads to gain some understanding of how these things work but still have a few questions that need to be answered before I can pull the trigger. Hope you don't mind me asking them here:


1. I've read that 98/99's utilize fuel tank pressure differential sensors that are not present on 97's and consequently using a 98/99 rom on a 97 will trigger a CEL. Is there a solution for this? I need to pass NJ inspections (they just plug into the OBD2 connector and do not do a sniffer test) and can't afford to have a CEL on.

2. Seems like Chrome ECU disables EGR by default; Is it possible to have an operating EGR on a 97 w/ Chrome ECU?

3. I read that 91-95's have EGR purge solenoid clicking problems. Since I have a 97 I am assuming that I do not have to worry about this... am I right?

4. The high 12 quarter mile time in your sig was with boost peaking at 16 psi, right? Do you feel there are still gains to be had on a stock car (I do have a downpipe) if I am not allowed to touch the stock boost map? I do a bit of autoxing for fun and the class I want to run does not allow altering the boost.

5. Are there any other known issues that may trigger a CEL on a stock 97?


Thanks in advance! Much appreciated

[vroom4]

I dont think STU allows swapping in a different ECU, but its one of those things if you dont modify timing tables or boost tables you will be fine.

[Ninja Performance]

Good questions.

-Chris

[Greg E]

1. I've read that 98/99's utilize fuel tank pressure differential sensors that are not present on 97's and consequently using a 98/99 rom on a 97 will trigger a CEL. Is there a solution for this? I need to pass NJ inspections (they just plug into the OBD2 connector and do not do a sniffer test) and can't afford to have a CEL on.

2. Seems like Chrome ECU disables EGR by default; Is it possible to have an operating EGR on a 97 w/ Chrome ECU?

3. I read that 91-95's have EGR purge solenoid clicking problems. Since I have a 97 I am assuming that I do not have to worry about this... am I right?

4. The high 12 quarter mile time in your sig was with boost peaking at 16 psi, right? Do you feel there are still gains to be had on a stock car (I do have a downpipe) if I am not allowed to touch the stock boost map? I do a bit of autoxing for fun and the class I want to run does not allow altering the boost.

5. Are there any other known issues that may trigger a CEL on a stock 97?

1. Although Chrome gives you the ability to cheat on the inspections, it is meant for off road use only!!

2. Wrong. EGR is enabled by default. There is a simple 0/1 bit trigger to disable it though. 0 = off, 1 = on

3. The "clicking" isn't so much an issue as it is an ear sore. The noise comes from trying to run an on/off style solenoid as an IPW solenoid like the BCS. Simply swapping the 91-95 style purge for the later style or switching to the stock BCS solenoid will cure this nuisance. You don't need to worry about this on your 97.

4. Boost pressure is irrelevant. Modifications that increase your engine load (airflow) are what's important. 16 psi on 9Bs means nothing because you're racing the car in the RPM ranges where the turbos can't flow enough air to generate that kind of pressure in the intake. My car actually made more power with less boost up top than it did running the turbos all out.

Throw your boost gauge away. Airflow = horse power.

5. No. Although I would strongly recommend re-reading the threads a couple more times till all this sticks.

[Greg E]

I dont think STU allows swapping in a different ECU, but its one of those things if you dont modify timing tables or boost tables you will be fine.

Its a difficult game to play. The ECU itself is a true Mitsubishi OBD2 complient device but any modifications to the ROM on it renders that compliance void.

[Prime12]

1. Although Chrome gives you the ability to cheat on the inspections, it is meant for off road use only!!

Gotcha. Let me ask the question in a different way:

Will running Chrome V2 on my 97 trigger a CEL due to 98/99's utilizing fuel tank pressure differential sensors that are not present on my 97? If it does, since I do not like / want any warning lights on my dash lit up, is there a work around this problem?

[Greg E]

Gotcha. Let me ask the question in a different way:

Will running Chrome V2 on my 97 trigger a CEL due to 98/99's utilizing fuel tank pressure differential sensors that are not present on my 97? If it does, since I do not like / want any warning lights on my dash lit up, is there a work around this problem?

Chrome gives you the ability to disable every CEL in the code in an area called the peripheries. Be aware that disabling the Periphery for any CEL also disables its ability to update the OBD2 monitors. This is what the inspection guys check. In order to force pass the monitors, you must follow some additional instructions lined out in the manual.

I do NOT condone my ROM mods to be used to cheat inspections. Such actions carry heavy penalties from the EPA if you get caught. This feature was put in place for vehicles to utilize chrome for track applications. You must keep your vehicle OBD2 complient if using chrome on the public streets.

[Prime12]

Chrome gives you the ability to disable every CEL in the code in an area called the peripheries. Be aware that disabling the Periphery for any CEL also disables its ability to update the OBD2 monitors. This is what the inspection guys check. In order to force pass the monitors, you must follow some additional instructions lined out in the manual.

I do NOT condone my ROM mods to be used to cheat inspections. Such actions carry heavy penalties from the EPA if you get caught. This feature was put in place for vehicles to utilize chrome for track applications. You must keep your vehicle OBD2 complient if using chrome on the public streets.

No worries. I'll just keep my stock 97 ECU for street driving then and use the flashable ecu just for autox events.

With that out of the way, I take that as of now, aside from disabling the particular CEL, there is no way to prevent that CEL from triggering on a 97?

[Greg E]

I take that as of now, aside from disabling the particular CEL, there is no way to prevent that CEL from triggering on a 97?

You turn it off, its disabled...

[Prime12]

God damn it I am an idiot. I didn't understand your response at first because I *thought* my 97 still had a fuel tank pressure sensor, just a different one from 98-99 that was incompatible with the flash ECU. I just looked up on ASA and looks like it never had one to begin with, lol. Now your response makes perfect sense. Thanks!